Laser-Scanned Programmable Perovskite-Nanocrystal Color Conversion Layers for White Light-Emitting Electrochemical Cells

We demonstrate that the correlated color temperatures (CCTs) of the white light-emitting electrochemical cells (LECs) can be tuned by modifying the optical properties of perovskite nanocrystals (NCs) in the color conversion layers (CCLs). By controlling the laser power, scanning number and duty cycle of the scanned grating patterns on perovskite-NC CCLs, the CCTs of the white LECs can be tuned from 2502 K to nearly 4300 K. This method is different from the conventional CCLs using multiple compositions of perovskite NCs to produce white light, so that it can avoid the inherent anion-exchange issue of perovskite NCs.